Doctors at Children’s of Alabama are working to answer a question that could help save the lives of infants with cyanotic congenital heart defects. In a new study, they’re asking which device is better: the Blalock-Taussig-Thomas (BTT) shunt or the ductus arteriosus (DA) stent.
The study is called the COMPASS Trial, short for Comparison of Methods of Pulmonary Blood Flow Augmentation in Neonates: Shunt Versus Stent. Children’s pediatric cardiologist Mark Law, MD, is the leading institutional investigator for Children’s.
“This is a very interesting study for our field,” Law said. “We have very few randomized controlled trials to show us which treatment strategy is best. There’s some thinking that DA stents may require additional, non-emergent interventions after they are implanted, and some data suggests the shunts may require a higher number of emergent interventions early on. We just don’t know.”
Of the two devices, the BTT shunt has been around longer. Developed in the 1950s, the shunt was the subject of a made-for-TV movie called “Something the Lord Made.” At the time, the shunt was lifesaving for babies with Tetralogy of Fallot. Today, it is used to manage babies with various heart defects that result in cyanosis, which causes insufficient blood flow from the heart to the lungs, resulting in low oxygen levels. These infants are often referred to as “blue babies.”
“It was field-changing when it was developed,” Law said of the shunt. However, it also requires open-chest surgery, which can lead to more complications and a higher risk of death.
DA stents, developed more recently, a much less invasive. A stent can be threaded into the ductus arteriosus, the artery that connects the aorta and pulmonary artery in newborns. Once in place, the stent is expanded to prevent the DA from closing.
Both the BTT shunt and the DA stent provide a stable source of blood flow to the lungs until the baby is large enough for an operation to repair the heart defect. Both options are relatively safe and effective, but both also present the risk of complications and death.
No one knows which is better because, until now, there’s never been a large study directly comparing the two procedures. The COMPASS Trial is a multi-institutional, NIH-funded study with the Pediatric Heart Network to see if one is safer and more efficacious than the other or if they are equally effective.
Investigators hope to enroll 300 newborns over the next two years and follow each through the first year of life. Most centers, including Children’s, should start enrolling patients this fall.
Overall survival and post-surgical complications are key endpoints for the study, as well as hospital length of stay and quality of life. Investigators also hope to learn which approach is best based on the child’s anatomy.
“We hope to come out the other end smarter and knowing which is the best therapy,” pediatric cardiologist William McMahon, MD, said. “Because right now, we just don’t know.”
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